Conventionally, there is proposed an active vibration noise control device for controlling an engine sound heard in a vehicle interior by a controlled sound output from a speaker so as to decrease the engine sound at a position of passenger's ear. For example, noticing that a vibration noise in a vehicle interior is generated in synchronization with a revolution of an output axis of an engine, there is proposed a technique for cancelling the noise in the vehicle interior on the basis of the revolution of the output axis of the engine by using an adaptive notch filter so that the vehicle interior becomes silent, in Patent Reference-1. The adaptive notch filter is a filter based on an adaptive control.
There are disclosed techniques related to the present invention in Patent Reference 2 and Non-Patent Reference 1.